package SocialNet;

import org.neo4j.graphdb.Direction;
import org.neo4j.graphdb.GraphDatabaseService;
import org.neo4j.graphdb.Node;
import org.neo4j.graphdb.Relationship;
import org.neo4j.graphdb.RelationshipType;
import org.neo4j.graphdb.Transaction;
import org.neo4j.graphdb.index.Index;
import org.neo4j.kernel.EmbeddedGraphDatabase;
import org.neo4j.kernel.impl.util.FileUtils;
import java.io.File;
import java.io.IOException;



public class GraphDatabase {

    private static final String DB_PATH = "graphdb";
    String greeting;
    // START SNIPPET: vars
    GraphDatabaseService graphDb;
    Index<Node> index;
    Node firstNode;
    Node secondNode;
    Relationship relationship;
    // END SNIPPET: vars

    public GraphDatabase () {
        System.out.println("initialize...");
        createDb();
    }

    // START SNIPPET: createReltype
    private static enum ReTy implements RelationshipType {
        KNOWS
    }
    // END SNIPPET: createReltype

    public static void main(final String[] args) {
        System.out.println("start...");
        GraphDatabase hello = new GraphDatabase();
        System.out.println("creat...");
        hello.createDb();
        System.out.println("remove...");
        hello.removeData();
        System.out.println("shut down...");
        hello.shutDown();
    }

    public void createDb() {
        clearDb();
        // START SNIPPET: startDb
        graphDb = new EmbeddedGraphDatabase( DB_PATH );
        registerShutdownHook( graphDb );
        // END SNIPPET: startDb

        // START SNIPPET: transaction
        Transaction tx = graphDb.beginTx();
        try
        {
            // Mutating operations go here
            // END SNIPPET: transaction
            // START SNIPPET: addData
            firstNode = graphDb.createNode();
            firstNode.setProperty( "message", "Hello, " );
            secondNode = graphDb.createNode();
            secondNode.setProperty( "message", "World!" );

            relationship = firstNode.createRelationshipTo( secondNode, ReTy.KNOWS );
            relationship.setProperty( "message", "brave Neo4j " );
            // END SNIPPET: addData

            // START SNIPPET: readData
            System.out.print( firstNode.getProperty( "message" ) );
            System.out.print( relationship.getProperty( "message" ) );
            System.out.println( secondNode.getProperty( "message" ) );
            // END SNIPPET: readData

            greeting = ( (String) firstNode.getProperty( "message" ) )
                    + ( (String) relationship.getProperty( "message" ) )
                    + ( (String) secondNode.getProperty( "message" ) );

            // START SNIPPET: transaction
            tx.success();
        }
        finally
        {
            tx.finish();
        }
        // END SNIPPET: transaction
    }

    private void clearDb() {
        try
        {
            FileUtils.deleteRecursively( new File( DB_PATH ) );
        }
        catch ( IOException e )
        {
            throw new RuntimeException( e );
        }
    }

    public void removeData() {
        Transaction tx = graphDb.beginTx();
        try
        {
            // START SNIPPET: removingData
            // let's remove the data
            firstNode.getSingleRelationship( ReTy.KNOWS, Direction.OUTGOING ).delete();
            firstNode.delete();
            secondNode.delete();
            // END SNIPPET: removingData

            tx.success();
        }
        finally
        {
            tx.finish();
        }
    }

    public void shutDown() {
        // START SNIPPET: shutdownServer
        graphDb.shutdown();
        // END SNIPPET: shutdownServer
    }

    // START SNIPPET: shutdownHook
    private static void registerShutdownHook( final GraphDatabaseService graphDb ) {
        // Registers a shutdown hook for the Neo4j instance so that it
        // shuts down nicely when the VM exits (even if you "Ctrl-C" the
        // running example before it's completed)
        Runtime.getRuntime().addShutdownHook( new Thread()
        {
            @Override
            public void run()
            {
                graphDb.shutdown();
            }
        } );
    }
    // END SNIPPET: shutdownHook
}
